Factor out Tor wrapper from plugin

bramble-android/src/main/java/org/briarproject/bramble/plugin/tor/AndroidTorPluginFactory.java

@@ -5,6 +5,7 @@ import android.app.Application;
 import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventExecutor;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.plugin.Backoff;
@@ -16,8 +17,9 @@ import org.briarproject.bramble.api.plugin.TorSocksPort;
 import org.briarproject.bramble.api.system.AndroidWakeLockManager;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
-import org.briarproject.bramble.api.system.ResourceProvider;
 import org.briarproject.bramble.api.system.WakefulIoExecutor;
+import org.briarproject.bramble.plugin.tor.wrapper.AndroidTorWrapper;
+import org.briarproject.bramble.plugin.tor.wrapper.TorWrapper;
 import org.briarproject.nullsafety.NotNullByDefault;
 
 import java.io.File;
@@ -28,6 +30,7 @@ import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 import javax.net.SocketFactory;
 
+import static android.os.Build.VERSION.SDK_INT;
 import static org.briarproject.bramble.util.AndroidUtils.getSupportedArchitectures;
 
 @Immutable
@@ -39,13 +42,13 @@ public class AndroidTorPluginFactory extends TorPluginFactory {
 
 	@Inject
 	AndroidTorPluginFactory(@IoExecutor Executor ioExecutor,
+			@EventExecutor Executor eventExecutor,
 			@WakefulIoExecutor Executor wakefulIoExecutor,
 			NetworkManager networkManager,
 			LocationUtils locationUtils,
 			EventBus eventBus,
 			SocketFactory torSocketFactory,
 			BackoffFactory backoffFactory,
-			ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
 			BatteryManager batteryManager,
 			Clock clock,
@@ -55,8 +58,8 @@ public class AndroidTorPluginFactory extends TorPluginFactory {
 			@TorControlPort int torControlPort,
 			Application app,
 			AndroidWakeLockManager wakeLockManager) {
-		super(ioExecutor, wakefulIoExecutor, networkManager, locationUtils,
+		super(ioExecutor, eventExecutor, wakefulIoExecutor, networkManager,
-				eventBus, torSocketFactory, backoffFactory, resourceProvider,
+				locationUtils, eventBus, torSocketFactory, backoffFactory,
 				circumventionProvider, batteryManager, clock, crypto,
 				torDirectory, torSocksPort, torControlPort);
 		this.app = app;
@@ -79,12 +82,18 @@ public class AndroidTorPluginFactory extends TorPluginFactory {
 	TorPlugin createPluginInstance(Backoff backoff,
 			TorRendezvousCrypto torRendezvousCrypto, PluginCallback callback,
 			String architecture) {
-		return new AndroidTorPlugin(ioExecutor,
+		TorWrapper tor = new AndroidTorWrapper(app, wakeLockManager,
-				wakefulIoExecutor, app, networkManager, locationUtils,
+				ioExecutor, eventExecutor, architecture, torDirectory,
-				torSocketFactory, clock, resourceProvider,
+				torSocksPort, torControlPort);
-				circumventionProvider, batteryManager, wakeLockManager,
+		// Android versions 7.1 and newer can verify Let's Encrypt TLS certs
-				backoff, torRendezvousCrypto, callback, architecture,
+		// signed with the IdentTrust DST Root X3 certificate. Older versions
-				MAX_LATENCY, MAX_IDLE_TIME, torDirectory, torSocksPort,
+		// of Android consider the certificate to have expired at the end of
-				torControlPort);
+		// September 2021.
+		boolean canVerifyLetsEncryptCerts = SDK_INT >= 25;
+		return new TorPlugin(ioExecutor, wakefulIoExecutor,
+				networkManager, locationUtils, torSocketFactory,
+				circumventionProvider, batteryManager, backoff,
+				torRendezvousCrypto, tor, callback, MAX_LATENCY,
+				MAX_IDLE_TIME, canVerifyLetsEncryptCerts);
 	}
 }

bramble-android/src/main/java/org/briarproject/bramble/plugin/tor/wrapper/AndroidTorWrapper.java

@@ -1,46 +1,36 @@
-package org.briarproject.bramble.plugin.tor;
+package org.briarproject.bramble.plugin.tor.wrapper;
 
 import android.app.Application;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
 import android.content.pm.PackageManager.NameNotFoundException;
+import android.content.res.Resources;
+import android.os.Build;
 
-import org.briarproject.bramble.api.battery.BatteryManager;
-import org.briarproject.bramble.api.network.NetworkManager;
-import org.briarproject.bramble.api.plugin.Backoff;
-import org.briarproject.bramble.api.plugin.PluginCallback;
 import org.briarproject.bramble.api.system.AndroidWakeLock;
 import org.briarproject.bramble.api.system.AndroidWakeLockManager;
-import org.briarproject.bramble.api.system.Clock;
+import org.briarproject.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.system.LocationUtils;
-import org.briarproject.bramble.api.system.ResourceProvider;
-import org.briarproject.bramble.util.AndroidUtils;
-import org.briarproject.nullsafety.MethodsNotNullByDefault;
-import org.briarproject.nullsafety.ParametersNotNullByDefault;
 
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
 import java.io.IOException;
+import java.io.InputStream;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.List;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipInputStream;
 
-import javax.net.SocketFactory;
-
-import androidx.annotation.ChecksSdkIntAtLeast;
-
 import static android.os.Build.VERSION.SDK_INT;
 import static java.util.Arrays.asList;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Logger.getLogger;
 
-@MethodsNotNullByDefault
+@NotNullByDefault
-@ParametersNotNullByDefault
+public class AndroidTorWrapper extends AbstractTorWrapper {
-class AndroidTorPlugin extends TorPlugin {
 
 	private static final List<String> LIBRARY_ARCHITECTURES =
 			asList("armeabi-v7a", "arm64-v8a", "x86", "x86_64");
@@ -50,37 +40,22 @@ class AndroidTorPlugin extends TorPlugin {
 	private static final String SNOWFLAKE_LIB_NAME = "libsnowflake.so";
 
 	private static final Logger LOG =
-			getLogger(AndroidTorPlugin.class.getName());
+			getLogger(AndroidTorWrapper.class.getName());
 
 	private final Application app;
 	private final AndroidWakeLock wakeLock;
 	private final File torLib, obfs4Lib, snowflakeLib;
 
-	AndroidTorPlugin(Executor ioExecutor,
+	public AndroidTorWrapper(Application app,
-			Executor wakefulIoExecutor,
-			Application app,
-			NetworkManager networkManager,
-			LocationUtils locationUtils,
-			SocketFactory torSocketFactory,
-			Clock clock,
-			ResourceProvider resourceProvider,
-			CircumventionProvider circumventionProvider,
-			BatteryManager batteryManager,
 			AndroidWakeLockManager wakeLockManager,
-			Backoff backoff,
+			Executor ioExecutor,
-			TorRendezvousCrypto torRendezvousCrypto,
+			Executor eventExecutor,
-			PluginCallback callback,
 			String architecture,
-			long maxLatency,
-			int maxIdleTime,
 			File torDirectory,
 			int torSocksPort,
 			int torControlPort) {
-		super(ioExecutor, wakefulIoExecutor, networkManager, locationUtils,
+		super(ioExecutor, eventExecutor, architecture, torDirectory,
-				torSocketFactory, clock, resourceProvider,
+				torSocksPort, torControlPort);
-				circumventionProvider, batteryManager, backoff,
-				torRendezvousCrypto, callback, architecture, maxLatency,
-				maxIdleTime, torDirectory, torSocksPort, torControlPort);
 		this.app = app;
 		wakeLock = wakeLockManager.createWakeLock("TorPlugin");
 		String nativeLibDir = app.getApplicationInfo().nativeLibraryDir;
@@ -106,22 +81,30 @@ class AndroidTorPlugin extends TorPlugin {
 	}
 
 	@Override
-	protected void enableNetwork(boolean enable) throws IOException {
+	public InputStream getResourceInputStream(String name, String extension) {
+		Resources res = app.getResources();
+		// Extension is ignored on Android, resources are retrieved without it
+		int resId = res.getIdentifier(name, "raw", app.getPackageName());
+		return res.openRawResource(resId);
+	}
+
+	@Override
+	public void enableNetwork(boolean enable) throws IOException {
 		if (enable) wakeLock.acquire();
-		super.enableNetwork(enable);
+		try {
-		if (!enable) wakeLock.release();
+			super.enableNetwork(enable);
+		} finally {
+			if (!enable) wakeLock.release();
+		}
 	}
 
 	@Override
-	@ChecksSdkIntAtLeast(api = 25)
+	public void stop() throws IOException {
-	protected boolean canVerifyLetsEncryptCerts() {
+		try {
-		return SDK_INT >= 25;
+			super.stop();
-	}
+		} finally {
-
+			wakeLock.release();
-	@Override
+		}
-	public void stop() {
-		super.stop();
-		wakeLock.release();
 	}
 
 	@Override
@@ -136,8 +119,8 @@ class AndroidTorPlugin extends TorPlugin {
 
 	@Override
 	protected File getSnowflakeExecutableFile() {
-		return snowflakeLib.exists()
+		return snowflakeLib.exists() ? snowflakeLib
-				? snowflakeLib : super.getSnowflakeExecutableFile();
+				: super.getSnowflakeExecutableFile();
 	}
 
 	@Override
@@ -184,6 +167,7 @@ class AndroidTorPlugin extends TorPlugin {
 		}
 		List<String> libPaths = getSupportedLibraryPaths(libName);
 		for (File apk : findApkFiles(sourceDir)) {
+			@SuppressWarnings("IOStreamConstructor")
 			ZipInputStream zin = new ZipInputStream(new FileInputStream(apk));
 			for (ZipEntry e = zin.getNextEntry(); e != null;
 					e = zin.getNextEntry()) {
@@ -228,11 +212,22 @@ class AndroidTorPlugin extends TorPlugin {
 	 */
 	private List<String> getSupportedLibraryPaths(String libName) {
 		List<String> architectures = new ArrayList<>();
-		for (String abi : AndroidUtils.getSupportedArchitectures()) {
+		for (String abi : getSupportedArchitectures()) {
 			if (LIBRARY_ARCHITECTURES.contains(abi)) {
 				architectures.add("lib/" + abi + "/" + libName);
 			}
 		}
 		return architectures;
 	}
+
+	private Collection<String> getSupportedArchitectures() {
+		List<String> abis = new ArrayList<>();
+		if (SDK_INT >= 21) {
+			abis.addAll(asList(Build.SUPPORTED_ABIS));
+		} else {
+			abis.add(Build.CPU_ABI);
+			if (Build.CPU_ABI2 != null) abis.add(Build.CPU_ABI2);
+		}
+		return abis;
+	}
 }

bramble-core/src/main/java/org/briarproject/bramble/plugin/PluginManagerImpl.java

@@ -40,9 +40,9 @@ import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicReference;
 import java.util.logging.Logger;
 
+import javax.annotation.concurrent.GuardedBy;
 import javax.annotation.concurrent.ThreadSafe;
 import javax.inject.Inject;
 
@@ -288,8 +288,10 @@ class PluginManagerImpl implements PluginManager, Service {
 	private class Callback implements PluginCallback {
 
 		private final TransportId id;
-		private final AtomicReference<State> state =
+		private final Object stateLock = new Object();
-				new AtomicReference<>(STARTING_STOPPING);
+
+		@GuardedBy("lock")
+		private State state = STARTING_STOPPING;
 
 		private Callback(TransportId id) {
 			this.id = id;
@@ -343,22 +345,26 @@ class PluginManagerImpl implements PluginManager, Service {
 
 		@Override
 		public void pluginStateChanged(State newState) {
-			State oldState = state.getAndSet(newState);
+			synchronized (stateLock) {
-			if (newState != oldState) {
+				if (newState != state) {
-				if (LOG.isLoggable(INFO)) {
+					State oldState = state;
-					LOG.info(id + " changed from state " + oldState
+					state = newState;
-							+ " to " + newState);
+					if (LOG.isLoggable(INFO)) {
+						LOG.info(id + " changed from state " + oldState
+								+ " to " + newState);
+					}
+					eventBus.broadcast(new TransportStateEvent(id, newState));
+					if (newState == ACTIVE) {
+						eventBus.broadcast(new TransportActiveEvent(id));
+					} else if (oldState == ACTIVE) {
+						eventBus.broadcast(new TransportInactiveEvent(id));
+					}
+				} else if (newState == DISABLED) {
+					// Broadcast an event even though the state hasn't changed,
+					// as the reasons for the plugin being disabled may have
+					// changed
+					eventBus.broadcast(new TransportStateEvent(id, newState));
 				}
-				eventBus.broadcast(new TransportStateEvent(id, newState));
-				if (newState == ACTIVE) {
-					eventBus.broadcast(new TransportActiveEvent(id));
-				} else if (oldState == ACTIVE) {
-					eventBus.broadcast(new TransportInactiveEvent(id));
-				}
-			} else if (newState == DISABLED) {
-				// Broadcast an event even though the state hasn't changed, as
-				// the reasons for the plugin being disabled may have changed
-				eventBus.broadcast(new TransportStateEvent(id, newState));
 			}
 		}
 

bramble-core/src/main/java/org/briarproject/bramble/plugin/tor/TorPlugin.java

@@ -1,8 +1,5 @@
 package org.briarproject.bramble.plugin.tor;
 
-import net.freehaven.tor.control.EventHandler;
-import net.freehaven.tor.control.TorControlConnection;
-
 import org.briarproject.bramble.PoliteExecutor;
 import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.battery.BatteryManager;
@@ -27,30 +24,21 @@ import org.briarproject.bramble.api.rendezvous.KeyMaterialSource;
 import org.briarproject.bramble.api.rendezvous.RendezvousEndpoint;
 import org.briarproject.bramble.api.settings.Settings;
 import org.briarproject.bramble.api.settings.event.SettingsUpdatedEvent;
-import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
-import org.briarproject.bramble.api.system.ResourceProvider;
 import org.briarproject.bramble.plugin.tor.CircumventionProvider.BridgeType;
-import org.briarproject.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.plugin.tor.wrapper.TorWrapper;
+import org.briarproject.bramble.plugin.tor.wrapper.TorWrapper.HiddenServiceProperties;
+import org.briarproject.bramble.plugin.tor.wrapper.TorWrapper.TorState;
+import org.briarproject.nullsafety.InterfaceNotNullByDefault;
 import org.briarproject.nullsafety.NotNullByDefault;
-import org.briarproject.nullsafety.ParametersNotNullByDefault;
 
-import java.io.ByteArrayInputStream;
-import java.io.EOFException;
-import java.io.File;
-import java.io.FileInputStream;
-import java.io.FileOutputStream;
 import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
 import java.net.InetSocketAddress;
 import java.net.ServerSocket;
 import java.net.Socket;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
-import java.util.Map;
-import java.util.Scanner;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
@@ -63,13 +51,9 @@ import javax.net.SocketFactory;
 
 import static java.util.Arrays.asList;
 import static java.util.Collections.emptyList;
-import static java.util.Collections.singletonList;
-import static java.util.Collections.singletonMap;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
-import static net.freehaven.tor.control.TorControlCommands.HS_ADDRESS;
-import static net.freehaven.tor.control.TorControlCommands.HS_PRIVKEY;
 import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
 import static org.briarproject.bramble.api.plugin.Plugin.State.DISABLED;
 import static org.briarproject.bramble.api.plugin.Plugin.State.ENABLING;
@@ -94,33 +78,16 @@ import static org.briarproject.bramble.api.plugin.TorConstants.REASON_MOBILE_DAT
 import static org.briarproject.bramble.plugin.tor.CircumventionProvider.BridgeType.MEEK;
 import static org.briarproject.bramble.plugin.tor.CircumventionProvider.BridgeType.SNOWFLAKE;
 import static org.briarproject.bramble.plugin.tor.TorRendezvousCrypto.SEED_BYTES;
-import static org.briarproject.bramble.util.IoUtils.copyAndClose;
 import static org.briarproject.bramble.util.IoUtils.tryToClose;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.PrivacyUtils.scrubOnion;
-import static org.briarproject.bramble.util.StringUtils.UTF_8;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
-import static org.briarproject.nullsafety.NullSafety.requireNonNull;
 
-@MethodsNotNullByDefault
+@InterfaceNotNullByDefault
-@ParametersNotNullByDefault
+class TorPlugin implements DuplexPlugin, EventListener {
-abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 	protected static final Logger LOG = getLogger(TorPlugin.class.getName());
 
-	private static final String[] EVENTS = {
-			"CIRC",
-			"ORCONN",
-			"STATUS_GENERAL",
-			"STATUS_CLIENT",
-			"HS_DESC",
-			"NOTICE",
-			"WARN",
-			"ERR"
-	};
-	private static final String OWNER = "__OwningControllerProcess";
-	private static final int COOKIE_TIMEOUT_MS = 3000;
-	private static final int COOKIE_POLLING_INTERVAL_MS = 200;
 	private static final Pattern ONION_V3 = Pattern.compile("[a-z2-7]{56}");
 
 	protected final Executor ioExecutor;
@@ -129,91 +96,63 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private final NetworkManager networkManager;
 	private final LocationUtils locationUtils;
 	private final SocketFactory torSocketFactory;
-	private final Clock clock;
+	private final CircumventionProvider circumventionProvider;
 	private final BatteryManager batteryManager;
 	private final Backoff backoff;
 	private final TorRendezvousCrypto torRendezvousCrypto;
+	private final TorWrapper tor;
 	private final PluginCallback callback;
-	private final String architecture;
-	private final CircumventionProvider circumventionProvider;
-	private final ResourceProvider resourceProvider;
 	private final long maxLatency;
 	private final int maxIdleTime;
+	private final boolean canVerifyLetsEncryptCerts;
 	private final int socketTimeout;
-	private final File torDirectory;
-	private final File configFile;
-	private final int torSocksPort;
-	private final int torControlPort;
-	private final File doneFile, cookieFile;
 	private final AtomicBoolean used = new AtomicBoolean(false);
 
 	protected final PluginState state = new PluginState();
 
-	private volatile Socket controlSocket = null;
-	private volatile TorControlConnection controlConnection = null;
 	private volatile Settings settings = null;
 
-	protected abstract int getProcessId();
-
-	protected abstract long getLastUpdateTime();
-
 	TorPlugin(Executor ioExecutor,
 			Executor wakefulIoExecutor,
 			NetworkManager networkManager,
 			LocationUtils locationUtils,
 			SocketFactory torSocketFactory,
-			Clock clock,
-			ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
 			BatteryManager batteryManager,
 			Backoff backoff,
 			TorRendezvousCrypto torRendezvousCrypto,
+			TorWrapper tor,
 			PluginCallback callback,
-			String architecture,
 			long maxLatency,
 			int maxIdleTime,
-			File torDirectory,
+			boolean canVerifyLetsEncryptCerts) {
-			int torSocksPort,
-			int torControlPort) {
 		this.ioExecutor = ioExecutor;
 		this.wakefulIoExecutor = wakefulIoExecutor;
 		this.networkManager = networkManager;
 		this.locationUtils = locationUtils;
 		this.torSocketFactory = torSocketFactory;
-		this.clock = clock;
-		this.resourceProvider = resourceProvider;
 		this.circumventionProvider = circumventionProvider;
 		this.batteryManager = batteryManager;
 		this.backoff = backoff;
 		this.torRendezvousCrypto = torRendezvousCrypto;
+		this.tor = tor;
 		this.callback = callback;
-		this.architecture = architecture;
 		this.maxLatency = maxLatency;
 		this.maxIdleTime = maxIdleTime;
-		if (maxIdleTime > Integer.MAX_VALUE / 2)
+		this.canVerifyLetsEncryptCerts = canVerifyLetsEncryptCerts;
+		if (maxIdleTime > Integer.MAX_VALUE / 2) {
 			socketTimeout = Integer.MAX_VALUE;
-		else socketTimeout = maxIdleTime * 2;
+		} else {
-		this.torDirectory = torDirectory;
+			socketTimeout = maxIdleTime * 2;
-		this.torSocksPort = torSocksPort;
+		}
-		this.torControlPort = torControlPort;
-		configFile = new File(torDirectory, "torrc");
-		doneFile = new File(torDirectory, "done");
-		cookieFile = new File(torDirectory, ".tor/control_auth_cookie");
 		// Don't execute more than one connection status check at a time
 		connectionStatusExecutor =
 				new PoliteExecutor("TorPlugin", ioExecutor, 1);
-	}
+		tor.setStateObserver(torState -> {
-
+			State s = state.getState(torState);
-	protected File getTorExecutableFile() {
+			if (s == ACTIVE) backoff.reset();
-		return new File(torDirectory, "tor");
+			callback.pluginStateChanged(s);
-	}
+		});
-
-	protected File getObfs4ExecutableFile() {
-		return new File(torDirectory, "obfs4proxy");
-	}
-
-	protected File getSnowflakeExecutableFile() {
-		return new File(torDirectory, "snowflake");
 	}
 
 	@Override
@@ -234,89 +173,18 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	@Override
 	public void start() throws PluginException {
 		if (used.getAndSet(true)) throw new IllegalStateException();
-		if (!torDirectory.exists()) {
-			if (!torDirectory.mkdirs()) {
-				LOG.warning("Could not create Tor directory.");
-				throw new PluginException();
-			}
-		}
 		// Load the settings
 		settings = callback.getSettings();
+		// Start Tor
 		try {
-			// Install or update the assets if necessary
+			tor.start();
-			if (!assetsAreUpToDate()) installAssets();
-			// Start from the default config every time
-			extract(getConfigInputStream(), configFile);
-		} catch (IOException e) {
-			throw new PluginException(e);
-		}
-		if (cookieFile.exists() && !cookieFile.delete())
-			LOG.warning("Old auth cookie not deleted");
-		// Start a new Tor process
-		LOG.info("Starting Tor");
-		File torFile = getTorExecutableFile();
-		String torPath = torFile.getAbsolutePath();
-		String configPath = configFile.getAbsolutePath();
-		String pid = String.valueOf(getProcessId());
-		Process torProcess;
-		ProcessBuilder pb =
-				new ProcessBuilder(torPath, "-f", configPath, OWNER, pid);
-		Map<String, String> env = pb.environment();
-		env.put("HOME", torDirectory.getAbsolutePath());
-		pb.directory(torDirectory);
-		pb.redirectErrorStream(true);
-		try {
-			torProcess = pb.start();
-		} catch (SecurityException | IOException e) {
-			throw new PluginException(e);
-		}
-		try {
-			// Wait for the Tor process to start
-			waitForTorToStart(torProcess);
-			// Wait for the auth cookie file to be created/updated
-			long start = clock.currentTimeMillis();
-			while (cookieFile.length() < 32) {
-				if (clock.currentTimeMillis() - start > COOKIE_TIMEOUT_MS) {
-					LOG.warning("Auth cookie not created");
-					if (LOG.isLoggable(INFO)) listFiles(torDirectory);
-					throw new PluginException();
-				}
-				//noinspection BusyWait
-				Thread.sleep(COOKIE_POLLING_INTERVAL_MS);
-			}
-			LOG.info("Auth cookie created");
 		} catch (InterruptedException e) {
 			LOG.warning("Interrupted while starting Tor");
 			Thread.currentThread().interrupt();
 			throw new PluginException();
-		}
-		try {
-			// Open a control connection and authenticate using the cookie file
-			controlSocket = new Socket("127.0.0.1", torControlPort);
-			controlConnection = new TorControlConnection(controlSocket);
-			controlConnection.authenticate(read(cookieFile));
-			// Tell Tor to exit when the control connection is closed
-			controlConnection.takeOwnership();
-			controlConnection.resetConf(singletonList(OWNER));
-			// Register to receive events from the Tor process
-			controlConnection.setEventHandler(this);
-			controlConnection.setEvents(asList(EVENTS));
-			// Check whether Tor has already bootstrapped
-			String info = controlConnection.getInfo("status/bootstrap-phase");
-			if (info != null && info.contains("PROGRESS=100")) {
-				LOG.info("Tor has already bootstrapped");
-				state.setBootstrapped();
-			}
-			// Check whether Tor has already built a circuit
-			info = controlConnection.getInfo("status/circuit-established");
-			if ("1".equals(info)) {
-				LOG.info("Tor has already built a circuit");
-				state.setCircuitBuilt(true);
-			}
 		} catch (IOException e) {
 			throw new PluginException(e);
 		}
-		state.setStarted();
 		// Check whether we're online
 		updateConnectionStatus(networkManager.getNetworkStatus(),
 				batteryManager.isCharging());
@@ -324,130 +192,6 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		bind();
 	}
 
-	private boolean assetsAreUpToDate() {
-		return doneFile.lastModified() > getLastUpdateTime();
-	}
-
-	private void installAssets() throws IOException {
-		// The done file may already exist from a previous installation
-		//noinspection ResultOfMethodCallIgnored
-		doneFile.delete();
-		installTorExecutable();
-		installObfs4Executable();
-		installSnowflakeExecutable();
-		if (!doneFile.createNewFile())
-			LOG.warning("Failed to create done file");
-	}
-
-	protected void extract(InputStream in, File dest) throws IOException {
-		OutputStream out = new FileOutputStream(dest);
-		copyAndClose(in, out);
-	}
-
-	protected void installTorExecutable() throws IOException {
-		if (LOG.isLoggable(INFO))
-			LOG.info("Installing Tor binary for " + architecture);
-		File torFile = getTorExecutableFile();
-		extract(getExecutableInputStream("tor"), torFile);
-		if (!torFile.setExecutable(true, true)) throw new IOException();
-	}
-
-	protected void installObfs4Executable() throws IOException {
-		if (LOG.isLoggable(INFO))
-			LOG.info("Installing obfs4proxy binary for " + architecture);
-		File obfs4File = getObfs4ExecutableFile();
-		extract(getExecutableInputStream("obfs4proxy"), obfs4File);
-		if (!obfs4File.setExecutable(true, true)) throw new IOException();
-	}
-
-	protected void installSnowflakeExecutable() throws IOException {
-		if (LOG.isLoggable(INFO))
-			LOG.info("Installing snowflake binary for " + architecture);
-		File snowflakeFile = getSnowflakeExecutableFile();
-		extract(getExecutableInputStream("snowflake"), snowflakeFile);
-		if (!snowflakeFile.setExecutable(true, true)) throw new IOException();
-	}
-
-	private InputStream getExecutableInputStream(String basename) {
-		String ext = getExecutableExtension();
-		return requireNonNull(resourceProvider
-				.getResourceInputStream(architecture + "/" + basename, ext));
-	}
-
-	protected String getExecutableExtension() {
-		return "";
-	}
-
-	private static void append(StringBuilder strb, String name, Object value) {
-		strb.append(name);
-		strb.append(" ");
-		strb.append(value);
-		strb.append("\n");
-	}
-
-	private InputStream getConfigInputStream() {
-		File dataDirectory = new File(torDirectory, ".tor");
-		StringBuilder strb = new StringBuilder();
-		append(strb, "ControlPort", torControlPort);
-		append(strb, "CookieAuthentication", 1);
-		append(strb, "DataDirectory", dataDirectory.getAbsolutePath());
-		append(strb, "DisableNetwork", 1);
-		append(strb, "RunAsDaemon", 1);
-		append(strb, "SafeSocks", 1);
-		append(strb, "SocksPort", torSocksPort);
-		strb.append("GeoIPFile\n");
-		strb.append("GeoIPv6File\n");
-		append(strb, "ConnectionPadding", 0);
-		String obfs4Path = getObfs4ExecutableFile().getAbsolutePath();
-		append(strb, "ClientTransportPlugin obfs4 exec", obfs4Path);
-		append(strb, "ClientTransportPlugin meek_lite exec", obfs4Path);
-		String snowflakePath = getSnowflakeExecutableFile().getAbsolutePath();
-		append(strb, "ClientTransportPlugin snowflake exec", snowflakePath);
-		return new ByteArrayInputStream(strb.toString().getBytes(UTF_8));
-	}
-
-	private void listFiles(File f) {
-		if (f.isDirectory()) {
-			File[] children = f.listFiles();
-			if (children != null) for (File child : children) listFiles(child);
-		} else {
-			LOG.info(f.getAbsolutePath() + " " + f.length());
-		}
-	}
-
-	private byte[] read(File f) throws IOException {
-		byte[] b = new byte[(int) f.length()];
-		FileInputStream in = new FileInputStream(f);
-		try {
-			int offset = 0;
-			while (offset < b.length) {
-				int read = in.read(b, offset, b.length - offset);
-				if (read == -1) throw new EOFException();
-				offset += read;
-			}
-			return b;
-		} finally {
-			tryToClose(in, LOG, WARNING);
-		}
-	}
-
-	protected void waitForTorToStart(Process torProcess)
-			throws InterruptedException, PluginException {
-		Scanner stdout = new Scanner(torProcess.getInputStream());
-		// Log the first line of stdout (contains Tor and library versions)
-		if (stdout.hasNextLine()) LOG.info(stdout.nextLine());
-		// Read the process's stdout (and redirected stderr) until it detaches
-		while (stdout.hasNextLine()) stdout.nextLine();
-		stdout.close();
-		// Wait for the process to detach or exit
-		int exit = torProcess.waitFor();
-		if (exit != 0) {
-			if (LOG.isLoggable(WARNING))
-				LOG.warning("Tor exited with value " + exit);
-			throw new PluginException();
-		}
-	}
-
 	private void bind() {
 		ioExecutor.execute(() -> {
 			// If there's already a port number stored in config, reuse it
@@ -471,9 +215,9 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 				return;
 			}
 			// Store the port number
-			String localPort = String.valueOf(ss.getLocalPort());
+			int localPort = ss.getLocalPort();
 			Settings s = new Settings();
-			s.put(PREF_TOR_PORT, localPort);
+			s.put(PREF_TOR_PORT, String.valueOf(localPort));
 			callback.mergeSettings(s);
 			// Create a hidden service if necessary
 			ioExecutor.execute(() -> publishHiddenService(localPort));
@@ -483,48 +227,28 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		});
 	}
 
-	private void publishHiddenService(String port) {
+	private void publishHiddenService(int localPort) {
-		if (!state.isTorRunning()) return;
+		if (!tor.isTorRunning()) return;
-		String privKey3 = settings.get(HS_PRIVATE_KEY_V3);
+		String privKey = settings.get(HS_PRIVATE_KEY_V3);
-		publishV3HiddenService(port, privKey3);
-	}
-
-	private void publishV3HiddenService(String port, @Nullable String privKey) {
 		LOG.info("Creating v3 hidden service");
-		Map<Integer, String> portLines = singletonMap(80, "127.0.0.1:" + port);
+		HiddenServiceProperties hsProps;
-		Map<String, String> response;
 		try {
-			// Use the control connection to set up the hidden service
+			hsProps = tor.publishHiddenService(localPort, 80, privKey);
-			if (privKey == null) {
-				response = controlConnection.addOnion("NEW:ED25519-V3",
-						portLines, null);
-			} else {
-				response = controlConnection.addOnion(privKey, portLines);
-			}
 		} catch (IOException e) {
 			logException(LOG, WARNING, e);
 			return;
 		}
-		if (!response.containsKey(HS_ADDRESS)) {
-			LOG.warning("Tor did not return a hidden service address");
-			return;
-		}
-		if (privKey == null && !response.containsKey(HS_PRIVKEY)) {
-			LOG.warning("Tor did not return a private key");
-			return;
-		}
-		String onion3 = response.get(HS_ADDRESS);
 		if (LOG.isLoggable(INFO)) {
-			LOG.info("V3 hidden service " + scrubOnion(onion3));
+			LOG.info("V3 hidden service " + scrubOnion(hsProps.onion));
 		}
 		if (privKey == null) {
 			// Publish the hidden service's onion hostname in transport props
 			TransportProperties p = new TransportProperties();
-			p.put(PROP_ONION_V3, onion3);
+			p.put(PROP_ONION_V3, hsProps.onion);
 			callback.mergeLocalProperties(p);
 			// Save the hidden service's private key for next time
 			Settings s = new Settings();
-			s.put(HS_PRIVATE_KEY_V3, response.get(HS_PRIVKEY));
+			s.put(HS_PRIVATE_KEY_V3, hsProps.privKey);
 			callback.mergeSettings(s);
 		}
 	}
@@ -547,50 +271,28 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		}
 	}
 
-	protected void enableNetwork(boolean enable) throws IOException {
-		if (!state.enableNetwork(enable)) return; // Unchanged
-		controlConnection.setConf("DisableNetwork", enable ? "0" : "1");
-	}
-
 	private void enableBridges(List<BridgeType> bridgeTypes, String countryCode)
 			throws IOException {
-		if (!state.setBridgeTypes(bridgeTypes)) return; // Unchanged
 		if (bridgeTypes.isEmpty()) {
-			controlConnection.setConf("UseBridges", "0");
+			tor.disableBridges();
-			controlConnection.resetConf(singletonList("Bridge"));
 		} else {
-			Collection<String> conf = new ArrayList<>();
+			List<String> bridges = new ArrayList<>();
-			conf.add("UseBridges 1");
-			boolean letsEncrypt = canVerifyLetsEncryptCerts();
 			for (BridgeType bridgeType : bridgeTypes) {
-				conf.addAll(circumventionProvider
+				bridges.addAll(circumventionProvider.getBridges(bridgeType,
-						.getBridges(bridgeType, countryCode, letsEncrypt));
+						countryCode, canVerifyLetsEncryptCerts));
 			}
-			controlConnection.setConf(conf);
+			tor.enableBridges(bridges);
 		}
 	}
 
-	/**
-	 * Returns true if this device can verify Let's Encrypt certificates signed
-	 * with the IdentTrust DST Root X3 certificate, which expired at the end of
-	 * September 2021.
-	 */
-	protected boolean canVerifyLetsEncryptCerts() {
-		return true;
-	}
-
 	@Override
 	public void stop() {
 		ServerSocket ss = state.setStopped();
 		tryToClose(ss, LOG, WARNING);
-		if (controlSocket != null && controlConnection != null) {
+		try {
-			try {
+			tor.stop();
-				LOG.info("Stopping Tor");
+		} catch (IOException e) {
-				controlConnection.shutdownTor("TERM");
+			logException(LOG, WARNING, e);
-				controlSocket.close();
-			} catch (IOException e) {
-				logException(LOG, WARNING, e);
-			}
 		}
 	}
 
@@ -701,6 +403,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		TransportProperties remoteProperties = new TransportProperties();
 		remoteProperties.put(PROP_ONION_V3, remoteOnion);
 		try {
+			@SuppressWarnings("resource")
 			ServerSocket ss = new ServerSocket();
 			ss.bind(new InetSocketAddress("127.0.0.1", 0));
 			int port = ss.getLocalPort();
@@ -717,9 +420,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 					LOG.info("Rendezvous server socket closed");
 				}
 			});
-			Map<Integer, String> portLines =
+			tor.publishHiddenService(port, 80, blob);
-					singletonMap(80, "127.0.0.1:" + port);
-			controlConnection.addOnion(blob, portLines);
 			return new RendezvousEndpoint() {
 
 				@Override
@@ -729,8 +430,11 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 				@Override
 				public void close() throws IOException {
-					controlConnection.delOnion(localOnion);
+					try {
-					tryToClose(ss, LOG, WARNING);
+						tor.removeHiddenService(localOnion);
+					} finally {
+						tryToClose(ss, LOG, WARNING);
+					}
 				}
 			};
 		} catch (IOException e) {
@@ -739,121 +443,6 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		}
 	}
 
-	@Override
-	public void circuitStatus(String status, String id, String path) {
-		// In case of races between receiving CIRCUIT_ESTABLISHED and setting
-		// DisableNetwork, set our circuitBuilt flag if not already set
-		if (status.equals("BUILT") && state.setCircuitBuilt(true)) {
-			LOG.info("Circuit built");
-			backoff.reset();
-		}
-	}
-
-	@Override
-	public void streamStatus(String status, String id, String target) {
-	}
-
-	@Override
-	public void orConnStatus(String status, String orName) {
-		if (LOG.isLoggable(INFO)) LOG.info("OR connection " + status);
-
-		if (status.equals("CONNECTED")) state.onOrConnectionConnected();
-		else if (status.equals("CLOSED")) state.onOrConnectionClosed();
-	}
-
-	@Override
-	public void bandwidthUsed(long read, long written) {
-	}
-
-	@Override
-	public void newDescriptors(List<String> orList) {
-	}
-
-	@Override
-	public void message(String severity, String msg) {
-		if (LOG.isLoggable(INFO)) LOG.info(severity + " " + msg);
-	}
-
-	@Override
-	public void unrecognized(String type, String msg) {
-		if (type.equals("STATUS_CLIENT")) {
-			handleClientStatus(removeSeverity(msg));
-		} else if (type.equals("STATUS_GENERAL")) {
-			handleGeneralStatus(removeSeverity(msg));
-		} else if (type.equals("HS_DESC") && msg.startsWith("UPLOADED")) {
-			String[] parts = msg.split(" ");
-			if (parts.length < 2) {
-				LOG.warning("Failed to parse HS_DESC UPLOADED event");
-			} else if (LOG.isLoggable(INFO)) {
-				LOG.info("V3 descriptor uploaded for " + scrubOnion(parts[1]));
-			}
-		}
-	}
-
-	@Override
-	public void controlConnectionClosed() {
-		if (state.isTorRunning()) {
-			// TODO: Restart the Tor process
-			LOG.warning("Control connection closed");
-		}
-	}
-
-	private String removeSeverity(String msg) {
-		return msg.replaceFirst("[^ ]+ ", "");
-	}
-
-	private void handleClientStatus(String msg) {
-		if (msg.startsWith("BOOTSTRAP PROGRESS=100")) {
-			LOG.info("Bootstrapped");
-			state.setBootstrapped();
-			backoff.reset();
-		} else if (msg.startsWith("CIRCUIT_ESTABLISHED")) {
-			if (state.setCircuitBuilt(true)) {
-				LOG.info("Circuit built");
-				backoff.reset();
-			}
-		} else if (msg.startsWith("CIRCUIT_NOT_ESTABLISHED")) {
-			if (state.setCircuitBuilt(false)) {
-				LOG.info("Circuit not built");
-				// TODO: Disable and re-enable network to prompt Tor to rebuild
-				//  its guard/bridge connections? This will also close any
-				//  established circuits, which might still be functioning
-			}
-		}
-	}
-
-	private void handleGeneralStatus(String msg) {
-		if (msg.startsWith("CLOCK_JUMPED")) {
-			Long time = parseLongArgument(msg, "TIME");
-			if (time != null && LOG.isLoggable(WARNING)) {
-				LOG.warning("Clock jumped " + time + " seconds");
-			}
-		} else if (msg.startsWith("CLOCK_SKEW")) {
-			Long skew = parseLongArgument(msg, "SKEW");
-			if (skew != null && LOG.isLoggable(WARNING)) {
-				LOG.warning("Clock is skewed by " + skew + " seconds");
-			}
-		}
-	}
-
-	@Nullable
-	private Long parseLongArgument(String msg, String argName) {
-		String[] args = msg.split(" ");
-		for (String arg : args) {
-			if (arg.startsWith(argName + "=")) {
-				try {
-					return Long.parseLong(arg.substring(argName.length() + 1));
-				} catch (NumberFormatException e) {
-					break;
-				}
-			}
-		}
-		if (LOG.isLoggable(WARNING)) {
-			LOG.warning("Failed to parse " + argName + " from '" + msg + "'");
-		}
-		return null;
-	}
-
 	@Override
 	public void eventOccurred(Event e) {
 		if (e instanceof SettingsUpdatedEvent) {
@@ -876,7 +465,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private void updateConnectionStatus(NetworkStatus status,
 			boolean charging) {
 		connectionStatusExecutor.execute(() -> {
-			if (!state.isTorRunning()) return;
+			if (!tor.isTorRunning()) return;
 			boolean online = status.isConnected();
 			boolean wifi = status.isWifi();
 			boolean ipv6Only = status.isIpv6Only();
@@ -960,41 +549,22 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			try {
 				if (enableNetwork) {
 					enableBridges(bridgeTypes, country);
-					enableConnectionPadding(enableConnectionPadding);
+					tor.enableConnectionPadding(enableConnectionPadding);
-					enableIpv6(ipv6Only);
+					tor.enableIpv6(ipv6Only);
 				}
-				enableNetwork(enableNetwork);
+				tor.enableNetwork(enableNetwork);
 			} catch (IOException e) {
 				logException(LOG, WARNING, e);
 			}
 		});
 	}
 
-	private void enableConnectionPadding(boolean enable) throws IOException {
-		if (!state.enableConnectionPadding(enable)) return; // Unchanged
-		controlConnection.setConf("ConnectionPadding", enable ? "1" : "0");
-	}
-
-	private void enableIpv6(boolean enable) throws IOException {
-		if (!state.enableIpv6(enable)) return; // Unchanged
-		controlConnection.setConf("ClientUseIPv4", enable ? "0" : "1");
-		controlConnection.setConf("ClientUseIPv6", enable ? "1" : "0");
-	}
-
 	@ThreadSafe
 	@NotNullByDefault
-	protected class PluginState {
+	private class PluginState {
 
 		@GuardedBy("this")
-		private boolean started = false,
+		private boolean settingsChecked = false;
-				stopped = false,
-				networkInitialised = false,
-				networkEnabled = false,
-				paddingEnabled = false,
-				ipv6Enabled = false,
-				bootstrapped = false,
-				circuitBuilt = false,
-				settingsChecked = false;
 
 		@GuardedBy("this")
 		private int reasonsDisabled = 0;
@@ -1003,84 +573,13 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		@Nullable
 		private ServerSocket serverSocket = null;
 
-		@GuardedBy("this")
-		private int orConnectionsConnected = 0;
-
-		@GuardedBy("this")
-		private List<BridgeType> bridgeTypes = emptyList();
-
-		private synchronized void setStarted() {
-			started = true;
-			callback.pluginStateChanged(getState());
-		}
-
-		@SuppressWarnings("BooleanMethodIsAlwaysInverted")
-		private synchronized boolean isTorRunning() {
-			return started && !stopped;
-		}
-
 		@Nullable
 		private synchronized ServerSocket setStopped() {
-			stopped = true;
 			ServerSocket ss = serverSocket;
 			serverSocket = null;
-			callback.pluginStateChanged(getState());
 			return ss;
 		}
 
-		private synchronized void setBootstrapped() {
-			boolean wasBootstrapped = bootstrapped;
-			bootstrapped = true;
-			if (!wasBootstrapped) callback.pluginStateChanged(getState());
-		}
-
-		/**
-		 * Sets the `circuitBuilt` flag and returns true if the flag has
-		 * changed.
-		 */
-		private synchronized boolean setCircuitBuilt(boolean built) {
-			if (built == circuitBuilt) return false; // Unchanged
-			circuitBuilt = built;
-			callback.pluginStateChanged(getState());
-			return true; // Changed
-		}
-
-		/**
-		 * Sets the `networkEnabled` flag and returns true if the flag has
-		 * changed.
-		 */
-		private synchronized boolean enableNetwork(boolean enable) {
-			boolean wasInitialised = networkInitialised;
-			boolean wasEnabled = networkEnabled;
-			networkInitialised = true;
-			networkEnabled = enable;
-			if (!enable) circuitBuilt = false;
-			if (!wasInitialised || enable != wasEnabled) {
-				callback.pluginStateChanged(getState());
-			}
-			return enable != wasEnabled;
-		}
-
-		/**
-		 * Sets the `paddingEnabled` flag and returns true if the flag has
-		 * changed. Doesn't affect getState().
-		 */
-		private synchronized boolean enableConnectionPadding(boolean enable) {
-			if (enable == paddingEnabled) return false; // Unchanged
-			paddingEnabled = enable;
-			return true; // Changed
-		}
-
-		/**
-		 * Sets the `ipv6Enabled` flag and returns true if the flag has
-		 * changed. Doesn't affect getState().
-		 */
-		private synchronized boolean enableIpv6(boolean enable) {
-			if (enable == ipv6Enabled) return false; // Unchanged
-			ipv6Enabled = enable;
-			return true; // Changed
-		}
-
 		private synchronized void setReasonsDisabled(int reasons) {
 			boolean wasChecked = settingsChecked;
 			settingsChecked = true;
@@ -1093,7 +592,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 		// Doesn't affect getState()
 		private synchronized boolean setServerSocket(ServerSocket ss) {
-			if (stopped || serverSocket != null) return false;
+			if (serverSocket != null || !tor.isTorRunning()) return false;
 			serverSocket = ss;
 			return true;
 		}
@@ -1103,57 +602,22 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			if (serverSocket == ss) serverSocket = null;
 		}
 
-		/**
+		private synchronized State getState() {
-		 * Sets the list of bridge types being used and returns true if the
+			return getState(tor.getTorState());
-		 * list has changed. The list is empty if bridges are disabled.
-		 * Doesn't affect getState().
-		 */
-		private synchronized boolean setBridgeTypes(List<BridgeType> types) {
-			if (types.equals(bridgeTypes)) return false; // Unchanged
-			bridgeTypes = types;
-			return true; // Changed
 		}
 
-		private synchronized State getState() {
+		private synchronized State getState(TorState torState) {
-			if (!started || stopped || !settingsChecked) {
+			if (torState == TorState.STARTING_STOPPING || !settingsChecked) {
 				return STARTING_STOPPING;
 			}
 			if (reasonsDisabled != 0) return DISABLED;
-			if (!networkInitialised) return ENABLING;
+			if (torState == TorState.CONNECTING) return ENABLING;
-			if (!networkEnabled) return INACTIVE;
+			if (torState == TorState.CONNECTED) return ACTIVE;
-			return bootstrapped && circuitBuilt && orConnectionsConnected > 0
+			return INACTIVE;
-					? ACTIVE : ENABLING;
 		}
 
 		private synchronized int getReasonsDisabled() {
 			return getState() == DISABLED ? reasonsDisabled : 0;
 		}
-
-		private synchronized void onOrConnectionConnected() {
-			int oldConnected = orConnectionsConnected;
-			orConnectionsConnected++;
-			logOrConnections();
-			if (oldConnected == 0) callback.pluginStateChanged(getState());
-		}
-
-		private synchronized void onOrConnectionClosed() {
-			int oldConnected = orConnectionsConnected;
-			orConnectionsConnected--;
-			if (orConnectionsConnected < 0) {
-				LOG.warning("Count was zero before connection closed");
-				orConnectionsConnected = 0;
-			}
-			logOrConnections();
-			if (orConnectionsConnected == 0 && oldConnected != 0) {
-				callback.pluginStateChanged(getState());
-			}
-		}
-
-		@GuardedBy("this")
-		private void logOrConnections() {
-			if (LOG.isLoggable(INFO)) {
-				LOG.info(orConnectionsConnected + " OR connections connected");
-			}
-		}
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/plugin/tor/TorPluginFactory.java

@@ -3,6 +3,7 @@ package org.briarproject.bramble.plugin.tor;
 import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventExecutor;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.plugin.Backoff;
@@ -17,7 +18,6 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
-import org.briarproject.bramble.api.system.ResourceProvider;
 import org.briarproject.bramble.api.system.WakefulIoExecutor;
 import org.briarproject.nullsafety.NotNullByDefault;
 
@@ -45,13 +45,12 @@ abstract class TorPluginFactory implements DuplexPluginFactory {
 	private static final int MAX_POLLING_INTERVAL = 10 * 60 * 1000; // 10 mins
 	private static final double BACKOFF_BASE = 1.2;
 
-	protected final Executor ioExecutor, wakefulIoExecutor;
+	protected final Executor ioExecutor, eventExecutor, wakefulIoExecutor;
 	protected final NetworkManager networkManager;
 	protected final LocationUtils locationUtils;
 	protected final EventBus eventBus;
 	protected final SocketFactory torSocketFactory;
 	protected final BackoffFactory backoffFactory;
-	protected final ResourceProvider resourceProvider;
 	protected final CircumventionProvider circumventionProvider;
 	protected final BatteryManager batteryManager;
 	protected final Clock clock;
@@ -61,13 +60,13 @@ abstract class TorPluginFactory implements DuplexPluginFactory {
 	protected final int torControlPort;
 
 	TorPluginFactory(@IoExecutor Executor ioExecutor,
+			@EventExecutor Executor eventExecutor,
 			@WakefulIoExecutor Executor wakefulIoExecutor,
 			NetworkManager networkManager,
 			LocationUtils locationUtils,
 			EventBus eventBus,
 			SocketFactory torSocketFactory,
 			BackoffFactory backoffFactory,
-			ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
 			BatteryManager batteryManager,
 			Clock clock,
@@ -76,13 +75,13 @@ abstract class TorPluginFactory implements DuplexPluginFactory {
 			@TorSocksPort int torSocksPort,
 			@TorControlPort int torControlPort) {
 		this.ioExecutor = ioExecutor;
+		this.eventExecutor = eventExecutor;
 		this.wakefulIoExecutor = wakefulIoExecutor;
 		this.networkManager = networkManager;
 		this.locationUtils = locationUtils;
 		this.eventBus = eventBus;
 		this.torSocketFactory = torSocketFactory;
 		this.backoffFactory = backoffFactory;
-		this.resourceProvider = resourceProvider;
 		this.circumventionProvider = circumventionProvider;
 		this.batteryManager = batteryManager;
 		this.clock = clock;

bramble-core/src/main/java/org/briarproject/bramble/plugin/tor/wrapper/AbstractTorWrapper.java

@@ -0,0 +1,673 @@
+package org.briarproject.bramble.plugin.tor.wrapper;
+
+import net.freehaven.tor.control.EventHandler;
+import net.freehaven.tor.control.TorControlConnection;
+
+import org.briarproject.nullsafety.InterfaceNotNullByDefault;
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.io.ByteArrayInputStream;
+import java.io.EOFException;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.Socket;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.Scanner;
+import java.util.concurrent.Executor;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+
+import static java.util.Arrays.asList;
+import static java.util.Collections.emptyList;
+import static java.util.Collections.singletonList;
+import static java.util.Collections.singletonMap;
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
+import static net.freehaven.tor.control.TorControlCommands.HS_ADDRESS;
+import static net.freehaven.tor.control.TorControlCommands.HS_PRIVKEY;
+import static org.briarproject.bramble.plugin.tor.wrapper.TorUtils.UTF_8;
+import static org.briarproject.bramble.plugin.tor.wrapper.TorUtils.copyAndClose;
+import static org.briarproject.bramble.plugin.tor.wrapper.TorUtils.scrubOnion;
+import static org.briarproject.bramble.plugin.tor.wrapper.TorUtils.tryToClose;
+import static org.briarproject.bramble.plugin.tor.wrapper.TorWrapper.TorState.CONNECTED;
+import static org.briarproject.bramble.plugin.tor.wrapper.TorWrapper.TorState.CONNECTING;
+import static org.briarproject.bramble.plugin.tor.wrapper.TorWrapper.TorState.DISABLED;
+import static org.briarproject.bramble.plugin.tor.wrapper.TorWrapper.TorState.STARTING_STOPPING;
+import static org.briarproject.nullsafety.NullSafety.requireNonNull;
+
+@InterfaceNotNullByDefault
+abstract class AbstractTorWrapper implements EventHandler, TorWrapper {
+
+	private static final String[] EVENTS = {
+			"CIRC",
+			"ORCONN",
+			"STATUS_GENERAL",
+			"STATUS_CLIENT",
+			"HS_DESC",
+			"NOTICE",
+			"WARN",
+			"ERR"
+	};
+
+	private static final String OWNER = "__OwningControllerProcess";
+	private static final int COOKIE_TIMEOUT_MS = 3000;
+	private static final int COOKIE_POLLING_INTERVAL_MS = 200;
+
+	protected final Executor ioExecutor;
+	protected final Executor eventExecutor;
+	private final String architecture;
+	private final File torDirectory, configFile, doneFile, cookieFile;
+	private final int torSocksPort;
+	private final int torControlPort;
+	private final AtomicBoolean used = new AtomicBoolean(false);
+
+	protected final NetworkState state = new NetworkState();
+
+	private volatile Socket controlSocket = null;
+	private volatile TorControlConnection controlConnection = null;
+
+	protected abstract int getProcessId();
+
+	protected abstract long getLastUpdateTime();
+
+	protected abstract InputStream getResourceInputStream(String name,
+			String extension);
+
+	AbstractTorWrapper(Executor ioExecutor,
+			Executor eventExecutor,
+			String architecture,
+			File torDirectory,
+			int torSocksPort,
+			int torControlPort) {
+		this.ioExecutor = ioExecutor;
+		this.eventExecutor = eventExecutor;
+		this.architecture = architecture;
+		this.torDirectory = torDirectory;
+		this.torSocksPort = torSocksPort;
+		this.torControlPort = torControlPort;
+		configFile = new File(torDirectory, "torrc");
+		doneFile = new File(torDirectory, "done");
+		cookieFile = new File(torDirectory, ".tor/control_auth_cookie");
+	}
+
+	protected File getTorExecutableFile() {
+		return new File(torDirectory, "tor");
+	}
+
+	protected File getObfs4ExecutableFile() {
+		return new File(torDirectory, "obfs4proxy");
+	}
+
+	protected File getSnowflakeExecutableFile() {
+		return new File(torDirectory, "snowflake");
+	}
+
+	@Override
+	public void setStateObserver(@Nullable StateObserver stateObserver) {
+		state.setObserver(stateObserver);
+	}
+
+	@Override
+	public void start() throws IOException, InterruptedException {
+		if (used.getAndSet(true)) throw new IllegalStateException();
+		if (!torDirectory.exists()) {
+			if (!torDirectory.mkdirs()) {
+				throw new IOException("Could not create Tor directory");
+			}
+		}
+		// Install or update the assets if necessary
+		if (!assetsAreUpToDate()) installAssets();
+		// Start from the default config every time
+		extract(getConfigInputStream(), configFile);
+		if (cookieFile.exists() && !cookieFile.delete())
+			LOG.warning("Old auth cookie not deleted");
+		// Start a new Tor process
+		LOG.info("Starting Tor");
+		File torFile = getTorExecutableFile();
+		String torPath = torFile.getAbsolutePath();
+		String configPath = configFile.getAbsolutePath();
+		String pid = String.valueOf(getProcessId());
+		Process torProcess;
+		ProcessBuilder pb =
+				new ProcessBuilder(torPath, "-f", configPath, OWNER, pid);
+		Map<String, String> env = pb.environment();
+		env.put("HOME", torDirectory.getAbsolutePath());
+		pb.directory(torDirectory);
+		pb.redirectErrorStream(true);
+		try {
+			torProcess = pb.start();
+		} catch (SecurityException e) {
+			throw new IOException(e);
+		}
+		// Wait for the Tor process to start
+		waitForTorToStart(torProcess);
+		// Wait for the auth cookie file to be created/updated
+		long start = System.currentTimeMillis();
+		while (cookieFile.length() < 32) {
+			if (System.currentTimeMillis() - start > COOKIE_TIMEOUT_MS) {
+				throw new IOException("Auth cookie not created");
+			}
+			//noinspection BusyWait
+			Thread.sleep(COOKIE_POLLING_INTERVAL_MS);
+		}
+		LOG.info("Auth cookie created");
+		// Open a control connection and authenticate using the cookie file
+		controlSocket = new Socket("127.0.0.1", torControlPort);
+		controlConnection = new TorControlConnection(controlSocket);
+		controlConnection.authenticate(read(cookieFile));
+		// Tell Tor to exit when the control connection is closed
+		controlConnection.takeOwnership();
+		controlConnection.resetConf(singletonList(OWNER));
+		// Register to receive events from the Tor process
+		controlConnection.setEventHandler(this);
+		controlConnection.setEvents(asList(EVENTS));
+		// Check whether Tor has already bootstrapped
+		String info = controlConnection.getInfo("status/bootstrap-phase");
+		if (info != null && info.contains("PROGRESS=100")) {
+			LOG.info("Tor has already bootstrapped");
+			state.setBootstrapped();
+		}
+		// Check whether Tor has already built a circuit
+		info = controlConnection.getInfo("status/circuit-established");
+		if ("1".equals(info)) {
+			LOG.info("Tor has already built a circuit");
+			state.setCircuitBuilt(true);
+		}
+		state.setStarted();
+	}
+
+	private boolean assetsAreUpToDate() {
+		return doneFile.lastModified() > getLastUpdateTime();
+	}
+
+	private void installAssets() throws IOException {
+		// The done file may already exist from a previous installation
+		//noinspection ResultOfMethodCallIgnored
+		doneFile.delete();
+		installTorExecutable();
+		installObfs4Executable();
+		installSnowflakeExecutable();
+		extract(getConfigInputStream(), configFile);
+		if (!doneFile.createNewFile()) {
+			LOG.warning("Failed to create done file");
+		}
+	}
+
+	protected void extract(InputStream in, File dest) throws IOException {
+		@SuppressWarnings("IOStreamConstructor")
+		OutputStream out = new FileOutputStream(dest);
+		copyAndClose(in, out);
+	}
+
+	protected void installTorExecutable() throws IOException {
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Installing Tor binary for " + architecture);
+		}
+		File torFile = getTorExecutableFile();
+		extract(getExecutableInputStream("tor"), torFile);
+		if (!torFile.setExecutable(true, true)) throw new IOException();
+	}
+
+	protected void installObfs4Executable() throws IOException {
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Installing obfs4proxy binary for " + architecture);
+		}
+		File obfs4File = getObfs4ExecutableFile();
+		extract(getExecutableInputStream("obfs4proxy"), obfs4File);
+		if (!obfs4File.setExecutable(true, true)) throw new IOException();
+	}
+
+	protected void installSnowflakeExecutable() throws IOException {
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Installing snowflake binary for " + architecture);
+		}
+		File snowflakeFile = getSnowflakeExecutableFile();
+		extract(getExecutableInputStream("snowflake"), snowflakeFile);
+		if (!snowflakeFile.setExecutable(true, true)) throw new IOException();
+	}
+
+	private InputStream getExecutableInputStream(String basename) {
+		String ext = getExecutableExtension();
+		return requireNonNull(
+				getResourceInputStream(architecture + "/" + basename, ext));
+	}
+
+	protected String getExecutableExtension() {
+		return "";
+	}
+
+	private static void append(StringBuilder strb, String name, Object value) {
+		strb.append(name);
+		strb.append(" ");
+		strb.append(value);
+		strb.append("\n");
+	}
+
+	private InputStream getConfigInputStream() {
+		File dataDirectory = new File(torDirectory, ".tor");
+		StringBuilder strb = new StringBuilder();
+		append(strb, "ControlPort", torControlPort);
+		append(strb, "CookieAuthentication", 1);
+		append(strb, "DataDirectory", dataDirectory.getAbsolutePath());
+		append(strb, "DisableNetwork", 1);
+		append(strb, "RunAsDaemon", 1);
+		append(strb, "SafeSocks", 1);
+		append(strb, "SocksPort", torSocksPort);
+		strb.append("GeoIPFile\n");
+		strb.append("GeoIPv6File\n");
+		append(strb, "ConnectionPadding", 0);
+		String obfs4Path = getObfs4ExecutableFile().getAbsolutePath();
+		append(strb, "ClientTransportPlugin obfs4 exec", obfs4Path);
+		append(strb, "ClientTransportPlugin meek_lite exec", obfs4Path);
+		String snowflakePath = getSnowflakeExecutableFile().getAbsolutePath();
+		append(strb, "ClientTransportPlugin snowflake exec", snowflakePath);
+		return new ByteArrayInputStream(strb.toString().getBytes(UTF_8));
+	}
+
+	private byte[] read(File f) throws IOException {
+		byte[] b = new byte[(int) f.length()];
+		FileInputStream in = new FileInputStream(f);
+		try {
+			int offset = 0;
+			while (offset < b.length) {
+				int read = in.read(b, offset, b.length - offset);
+				if (read == -1) throw new EOFException();
+				offset += read;
+			}
+			return b;
+		} finally {
+			tryToClose(in, LOG, WARNING);
+		}
+	}
+
+	protected void waitForTorToStart(Process torProcess)
+			throws InterruptedException, IOException {
+		Scanner stdout = new Scanner(torProcess.getInputStream());
+		// Log the first line of stdout (contains Tor and library versions)
+		if (stdout.hasNextLine()) LOG.info(stdout.nextLine());
+		// Read the process's stdout (and redirected stderr) until it detaches
+		while (stdout.hasNextLine()) stdout.nextLine();
+		stdout.close();
+		// Wait for the process to detach or exit
+		int exit = torProcess.waitFor();
+		if (exit != 0) throw new IOException("Tor exited with value " + exit);
+	}
+
+	@Override
+	public HiddenServiceProperties publishHiddenService(int localPort,
+			int remotePort, @Nullable String privKey) throws IOException {
+		Map<Integer, String> portLines =
+				singletonMap(remotePort, "127.0.0.1:" + localPort);
+		// Use the control connection to set up the hidden service
+		Map<String, String> response;
+		if (privKey == null) {
+			response = getControlConnection().addOnion("NEW:ED25519-V3",
+					portLines, null);
+		} else {
+			response = getControlConnection().addOnion(privKey, portLines);
+		}
+		if (!response.containsKey(HS_ADDRESS)) {
+			throw new IOException("Missing hidden service address");
+		}
+		if (privKey == null && !response.containsKey(HS_PRIVKEY)) {
+			throw new IOException("Missing private key");
+		}
+		String onion = response.get(HS_ADDRESS);
+		if (privKey == null) privKey = response.get(HS_PRIVKEY);
+		return new HiddenServiceProperties(onion, privKey);
+	}
+
+	@Override
+	public void removeHiddenService(String onion) throws IOException {
+		getControlConnection().delOnion(onion);
+	}
+
+	@Override
+	public void enableNetwork(boolean enable) throws IOException {
+		if (!state.enableNetwork(enable)) return; // Unchanged
+		getControlConnection().setConf("DisableNetwork", enable ? "0" : "1");
+	}
+
+	@Override
+	public void enableBridges(List<String> bridges) throws IOException {
+		if (!state.setBridges(bridges)) return; // Unchanged
+		List<String> conf = new ArrayList<>(bridges.size() + 1);
+		conf.add("UseBridges 1");
+		conf.addAll(bridges);
+		getControlConnection().setConf(conf);
+	}
+
+	@Override
+	public void disableBridges() throws IOException {
+		if (!state.setBridges(emptyList())) return; // Unchanged
+		getControlConnection().setConf("UseBridges", "0");
+	}
+
+	@Override
+	public void stop() throws IOException {
+		state.setStopped();
+		if (controlSocket != null && controlConnection != null) {
+			LOG.info("Stopping Tor");
+			try {
+				controlConnection.shutdownTor("TERM");
+			} finally {
+				tryToClose(controlSocket, LOG, WARNING);
+			}
+		}
+	}
+
+	@Override
+	public void circuitStatus(String status, String id, String path) {
+		// In case of races between receiving CIRCUIT_ESTABLISHED and setting
+		// DisableNetwork, set our circuitBuilt flag if not already set
+		if (status.equals("BUILT") && state.setCircuitBuilt(true)) {
+			LOG.info("Circuit built");
+		}
+	}
+
+	@Override
+	public void streamStatus(String status, String id, String target) {
+	}
+
+	@Override
+	public void orConnStatus(String status, String orName) {
+		if (LOG.isLoggable(INFO)) LOG.info("OR connection " + status);
+
+		if (status.equals("CONNECTED")) state.onOrConnectionConnected();
+		else if (status.equals("CLOSED")) state.onOrConnectionClosed();
+	}
+
+	@Override
+	public void bandwidthUsed(long read, long written) {
+	}
+
+	@Override
+	public void newDescriptors(List<String> orList) {
+	}
+
+	@Override
+	public void message(String severity, String msg) {
+		if (LOG.isLoggable(INFO)) LOG.info(severity + " " + msg);
+	}
+
+	@Override
+	public void unrecognized(String type, String msg) {
+		if (type.equals("STATUS_CLIENT")) {
+			handleClientStatus(removeSeverity(msg));
+		} else if (type.equals("STATUS_GENERAL")) {
+			handleGeneralStatus(removeSeverity(msg));
+		} else if (type.equals("HS_DESC") && msg.startsWith("UPLOADED")) {
+			String[] parts = msg.split(" ");
+			if (parts.length < 2) {
+				LOG.warning("Failed to parse HS_DESC UPLOADED event");
+			} else if (LOG.isLoggable(INFO)) {
+				LOG.info("V3 descriptor uploaded for " + scrubOnion(parts[1]));
+			}
+		}
+	}
+
+	private String removeSeverity(String msg) {
+		return msg.replaceFirst("[^ ]+ ", "");
+	}
+
+	private void handleClientStatus(String msg) {
+		if (msg.startsWith("BOOTSTRAP PROGRESS=100")) {
+			LOG.info("Bootstrapped");
+			state.setBootstrapped();
+		} else if (msg.startsWith("CIRCUIT_ESTABLISHED")) {
+			if (state.setCircuitBuilt(true)) LOG.info("Circuit built");
+		} else if (msg.startsWith("CIRCUIT_NOT_ESTABLISHED")) {
+			if (state.setCircuitBuilt(false)) {
+				LOG.info("Circuit not built");
+				// TODO: Disable and re-enable network to prompt Tor to rebuild
+				//  its guard/bridge connections? This will also close any
+				//  established circuits, which might still be functioning
+			}
+		}
+	}
+
+	private void handleGeneralStatus(String msg) {
+		if (msg.startsWith("CLOCK_JUMPED")) {
+			Long time = parseLongArgument(msg, "TIME");
+			if (time != null && LOG.isLoggable(WARNING)) {
+				LOG.warning("Clock jumped " + time + " seconds");
+			}
+		} else if (msg.startsWith("CLOCK_SKEW")) {
+			Long skew = parseLongArgument(msg, "SKEW");
+			if (skew != null && LOG.isLoggable(WARNING)) {
+				LOG.warning("Clock is skewed by " + skew + " seconds");
+			}
+		}
+	}
+
+	@Nullable
+	private Long parseLongArgument(String msg, String argName) {
+		String[] args = msg.split(" ");
+		for (String arg : args) {
+			if (arg.startsWith(argName + "=")) {
+				try {
+					return Long.parseLong(arg.substring(argName.length() + 1));
+				} catch (NumberFormatException e) {
+					break;
+				}
+			}
+		}
+		if (LOG.isLoggable(WARNING)) {
+			LOG.warning("Failed to parse " + argName + " from '" + msg + "'");
+		}
+		return null;
+	}
+
+	@Override
+	public void controlConnectionClosed() {
+		if (state.isTorRunning()) {
+			// TODO: Restart the Tor process
+			LOG.warning("Control connection closed");
+		}
+	}
+
+	@Override
+	public void enableConnectionPadding(boolean enable) throws IOException {
+		if (!state.enableConnectionPadding(enable)) return; // Unchanged
+		getControlConnection().setConf("ConnectionPadding", enable ? "1" : "0");
+	}
+
+	@Override
+	public void enableIpv6(boolean enable) throws IOException {
+		if (!state.enableIpv6(enable)) return; // Unchanged
+		getControlConnection().setConf("ClientUseIPv4", enable ? "0" : "1");
+		getControlConnection().setConf("ClientUseIPv6", enable ? "1" : "0");
+	}
+
+	@Override
+	public TorState getTorState() {
+		return state.getState();
+	}
+
+	@Override
+	public boolean isTorRunning() {
+		return state.isTorRunning();
+	}
+
+	private TorControlConnection getControlConnection() throws IOException {
+		TorControlConnection controlConnection = this.controlConnection;
+		if (controlConnection == null) {
+			throw new IOException("Control connection not opened");
+		}
+		return controlConnection;
+	}
+
+	@ThreadSafe
+	@NotNullByDefault
+	private class NetworkState {
+
+		@GuardedBy("this")
+		@Nullable
+		private StateObserver observer = null;
+
+		@GuardedBy("this")
+		private boolean started = false,
+				stopped = false,
+				networkInitialised = false,
+				networkEnabled = false,
+				paddingEnabled = false,
+				ipv6Enabled = false,
+				bootstrapped = false,
+				circuitBuilt = false;
+
+		@GuardedBy("this")
+		private int orConnectionsConnected = 0;
+
+		@GuardedBy("this")
+		@Nullable
+		private TorState state = null;
+
+		private synchronized void setObserver(
+				@Nullable StateObserver observer) {
+			this.observer = observer;
+		}
+
+		@GuardedBy("this")
+		private void updateObserver() {
+			TorState newState = getState();
+			if (newState != state) {
+				state = newState;
+				// Post the new state to the event executor. The contract of
+				// this executor is to execute tasks in the order they're
+				// submitted, so state changes will be observed in the correct
+				// order but outside the lock
+				if (observer != null) {
+					eventExecutor.execute(() ->
+							observer.observeState(newState));
+				}
+			}
+		}
+
+		@GuardedBy("this")
+		private List<String> bridges = emptyList();
+
+		private synchronized void setStarted() {
+			started = true;
+			updateObserver();
+		}
+
+		@SuppressWarnings("BooleanMethodIsAlwaysInverted")
+		private synchronized boolean isTorRunning() {
+			return started && !stopped;
+		}
+
+		private synchronized void setStopped() {
+			stopped = true;
+			updateObserver();
+		}
+
+		private synchronized void setBootstrapped() {
+			if (bootstrapped) return;
+			bootstrapped = true;
+			updateObserver();
+		}
+
+		/**
+		 * Sets the `circuitBuilt` flag and returns true if the flag has
+		 * changed.
+		 */
+		private synchronized boolean setCircuitBuilt(boolean built) {
+			if (built == circuitBuilt) return false; // Unchanged
+			circuitBuilt = built;
+			updateObserver();
+			return true; // Changed
+		}
+
+		/**
+		 * Sets the `networkEnabled` flag and returns true if the flag has
+		 * changed.
+		 */
+		private synchronized boolean enableNetwork(boolean enable) {
+			boolean wasInitialised = networkInitialised;
+			boolean wasEnabled = networkEnabled;
+			networkInitialised = true;
+			networkEnabled = enable;
+			if (!enable) circuitBuilt = false;
+			if (!wasInitialised || enable != wasEnabled) {
+				updateObserver();
+			}
+			return enable != wasEnabled;
+		}
+
+		/**
+		 * Sets the `paddingEnabled` flag and returns true if the flag has
+		 * changed. Doesn't affect getState().
+		 */
+		private synchronized boolean enableConnectionPadding(boolean enable) {
+			if (enable == paddingEnabled) return false; // Unchanged
+			paddingEnabled = enable;
+			return true; // Changed
+		}
+
+		/**
+		 * Sets the `ipv6Enabled` flag and returns true if the flag has
+		 * changed. Doesn't affect getState().
+		 */
+		private synchronized boolean enableIpv6(boolean enable) {
+			if (enable == ipv6Enabled) return false; // Unchanged
+			ipv6Enabled = enable;
+			return true; // Changed
+		}
+
+		/**
+		 * Sets the list of bridges being used and returns true if the
+		 * list has changed. The list is empty if bridges are disabled.
+		 * Doesn't affect getState().
+		 */
+		@SuppressWarnings("BooleanMethodIsAlwaysInverted")
+		private synchronized boolean setBridges(List<String> bridges) {
+			if (this.bridges.equals(bridges)) return false; // Unchanged
+			this.bridges = bridges;
+			return true; // Changed
+		}
+
+		private synchronized TorState getState() {
+			if (!started || stopped) return STARTING_STOPPING;
+			if (!networkInitialised) return CONNECTING;
+			if (!networkEnabled) return DISABLED;
+			return bootstrapped && circuitBuilt && orConnectionsConnected > 0
+					? CONNECTED : CONNECTING;
+		}
+
+		private synchronized void onOrConnectionConnected() {
+			int oldConnected = orConnectionsConnected;
+			orConnectionsConnected++;
+			logOrConnections();
+			if (oldConnected == 0) updateObserver();
+		}
+
+		private synchronized void onOrConnectionClosed() {
+			int oldConnected = orConnectionsConnected;
+			orConnectionsConnected--;
+			if (orConnectionsConnected < 0) {
+				LOG.warning("Count was zero before connection closed");
+				orConnectionsConnected = 0;
+			}
+			logOrConnections();
+			if (orConnectionsConnected == 0 && oldConnected != 0) {
+				updateObserver();
+			}
+		}
+
+		@GuardedBy("this")
+		private void logOrConnections() {
+			if (LOG.isLoggable(INFO)) {
+				LOG.info(orConnectionsConnected + " OR connections connected");
+			}
+		}
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/plugin/tor/wrapper/TorUtils.java

@@ -0,0 +1,66 @@
+package org.briarproject.bramble.plugin.tor.wrapper;
+
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.net.Socket;
+import java.nio.charset.Charset;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+
+import static java.util.logging.Level.WARNING;
+import static org.briarproject.bramble.plugin.tor.wrapper.TorWrapper.LOG;
+
+@NotNullByDefault
+class TorUtils {
+
+	@SuppressWarnings("CharsetObjectCanBeUsed")
+	static final Charset UTF_8 = Charset.forName("UTF-8");
+
+	static String scrubOnion(String onion) {
+		// Keep first three characters of onion address
+		return onion.substring(0, 3) + "[scrubbed]";
+	}
+
+	static void copyAndClose(InputStream in, OutputStream out) {
+		byte[] buf = new byte[4096];
+		try {
+			while (true) {
+				int read = in.read(buf);
+				if (read == -1) break;
+				out.write(buf, 0, read);
+			}
+			in.close();
+			out.flush();
+			out.close();
+		} catch (IOException e) {
+			tryToClose(in, LOG, WARNING);
+			tryToClose(out, LOG, WARNING);
+		}
+	}
+
+	static void tryToClose(@Nullable Closeable c, Logger logger, Level level) {
+		try {
+			if (c != null) c.close();
+		} catch (IOException e) {
+			logException(logger, level, e);
+		}
+	}
+
+	static void tryToClose(@Nullable Socket s, Logger logger, Level level) {
+		try {
+			if (s != null) s.close();
+		} catch (IOException e) {
+			logException(logger, level, e);
+		}
+	}
+
+	private static void logException(Logger logger, Level level, Throwable t) {
+		if (logger.isLoggable(level)) logger.log(level, t.toString(), t);
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/plugin/tor/wrapper/TorWrapper.java

@@ -0,0 +1,153 @@
+package org.briarproject.bramble.plugin.tor.wrapper;
+
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+
+import static java.util.logging.Logger.getLogger;
+
+@NotNullByDefault
+public interface TorWrapper {
+
+	Logger LOG = getLogger(TorWrapper.class.getName());
+
+	/**
+	 * Starts the Tor process.
+	 * <p>
+	 * This method must only be called once. To restart the Tor process, stop
+	 * this wrapper instance and then create a new instance.
+	 */
+	void start() throws IOException, InterruptedException;
+
+	/**
+	 * Tell the Tor process to stop and returns without waiting for the
+	 * process to exit.
+	 */
+	void stop() throws IOException;
+
+	/**
+	 * Sets an observer for observing the state of the wrapper, replacing any
+	 * existing observer, or removes any existing observer if the argument is
+	 * null.
+	 */
+	void setStateObserver(@Nullable StateObserver stateObserver);
+
+	/**
+	 * Returns the current state of the wrapper.
+	 */
+	TorState getTorState();
+
+	/**
+	 * Returns true if the wrapper has been {@link #start() started} and not
+	 * yet {@link #stop()} stopped.
+	 */
+	@SuppressWarnings("BooleanMethodIsAlwaysInverted")
+	boolean isTorRunning();
+
+	/**
+	 * Publishes an ephemeral hidden service.
+	 *
+	 * @param localPort The local port on which the service is listening.
+	 * @param remotePort The port number that clients of the service will see.
+	 * @param privateKey The private key of the hidden service, in the form
+	 * returned by a previous call to this method, or null if a new service
+	 * should be created.
+	 */
+	HiddenServiceProperties publishHiddenService(int localPort,
+			int remotePort, @Nullable String privateKey) throws IOException;
+
+	/**
+	 * Removes (unpublishes) an ephemeral hidden service that was created by
+	 * calling {@link #publishHiddenService(int, int, String)}.
+	 */
+	void removeHiddenService(String onion) throws IOException;
+
+	/**
+	 * Enables or disables the Tor process's network connection. The network
+	 * connection is disabled by default.
+	 */
+	void enableNetwork(boolean enable) throws IOException;
+
+	/**
+	 * Configures Tor to use the given list of bridges for connecting to the
+	 * Tor network. Bridges are not used by default.
+	 * <p>
+	 * Each item in the list should be a bridge line in the same
+	 * format that would be used in a torrc file (including the Bridge keyword).
+	 */
+	void enableBridges(List<String> bridges) throws IOException;
+
+	/**
+	 * Configures Tor not to use bridges for connecting to the Tor network.
+	 * Bridges are not used by default.
+	 */
+	void disableBridges() throws IOException;
+
+	/**
+	 * Enables or disables connection padding. Padding is disabled by default.
+	 */
+	void enableConnectionPadding(boolean enable) throws IOException;
+
+	/**
+	 * Configures Tor to use IPv6 or IPv4 for connecting to the Tor network.
+	 * IPv4 is used by default.
+	 */
+	void enableIpv6(boolean ipv6Only) throws IOException;
+
+	/**
+	 * The state of the Tor wrapper.
+	 */
+	enum TorState {
+
+		/**
+		 * The Tor process is either starting or stopping.
+		 */
+		STARTING_STOPPING,
+
+		/**
+		 * The Tor process has started, its network connection is enabled, and
+		 * it is connecting (or reconnecting) to the Tor network.
+		 */
+		CONNECTING,
+
+		/**
+		 * The Tor process has started, its network connection is enabled, and
+		 * it has connected to the Tor network. In this state it should be
+		 * possible to make connections via the SOCKS port.
+		 */
+		CONNECTED,
+
+		/**
+		 * The Tor process has started but its network connection is disabled.
+		 */
+		DISABLED
+	}
+
+	/**
+	 * An interface for observing changes to the {@link TorState state} of the
+	 * Tor process.
+	 */
+	interface StateObserver {
+
+		/**
+		 * This method is called whenever the state of the Tor process changes.
+		 * The call happens on the event executor supplied to the wrapper's
+		 * constructor.
+		 */
+		void observeState(TorState s);
+	}
+
+	class HiddenServiceProperties {
+
+		public final String onion, privKey;
+
+		HiddenServiceProperties(String onion, String privKey) {
+			this.onion = onion;
+			this.privKey = privKey;
+		}
+	}
+}

bramble-java/src/main/java/org/briarproject/bramble/plugin/tor/JavaTorPlugin.java

@@ -1,62 +0,0 @@
-package org.briarproject.bramble.plugin.tor;
-
-import org.briarproject.bramble.api.battery.BatteryManager;
-import org.briarproject.bramble.api.network.NetworkManager;
-import org.briarproject.bramble.api.plugin.Backoff;
-import org.briarproject.bramble.api.plugin.PluginCallback;
-import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.bramble.api.system.LocationUtils;
-import org.briarproject.bramble.api.system.ResourceProvider;
-import org.briarproject.nullsafety.NotNullByDefault;
-
-import java.io.File;
-import java.net.URI;
-import java.net.URISyntaxException;
-import java.security.CodeSource;
-import java.util.concurrent.Executor;
-
-import javax.net.SocketFactory;
-
-@NotNullByDefault
-abstract class JavaTorPlugin extends TorPlugin {
-
-	JavaTorPlugin(Executor ioExecutor,
-			Executor wakefulIoExecutor,
-			NetworkManager networkManager,
-			LocationUtils locationUtils,
-			SocketFactory torSocketFactory,
-			Clock clock,
-			ResourceProvider resourceProvider,
-			CircumventionProvider circumventionProvider,
-			BatteryManager batteryManager,
-			Backoff backoff,
-			TorRendezvousCrypto torRendezvousCrypto,
-			PluginCallback callback,
-			String architecture,
-			long maxLatency,
-			int maxIdleTime,
-			File torDirectory,
-			int torSocksPort,
-			int torControlPort) {
-		super(ioExecutor, wakefulIoExecutor, networkManager, locationUtils,
-				torSocketFactory, clock, resourceProvider,
-				circumventionProvider, batteryManager, backoff,
-				torRendezvousCrypto, callback, architecture,
-				maxLatency, maxIdleTime, torDirectory, torSocksPort,
-				torControlPort);
-	}
-
-	@Override
-	protected long getLastUpdateTime() {
-		CodeSource codeSource =
-				getClass().getProtectionDomain().getCodeSource();
-		if (codeSource == null) throw new AssertionError("CodeSource null");
-		try {
-			URI path = codeSource.getLocation().toURI();
-			File file = new File(path);
-			return file.lastModified();
-		} catch (URISyntaxException e) {
-			throw new AssertionError(e);
-		}
-	}
-}

bramble-java/src/main/java/org/briarproject/bramble/plugin/tor/UnixTorPlugin.java

@@ -1,60 +0,0 @@
-package org.briarproject.bramble.plugin.tor;
-
-import com.sun.jna.Library;
-import com.sun.jna.Native;
-
-import org.briarproject.bramble.api.battery.BatteryManager;
-import org.briarproject.bramble.api.network.NetworkManager;
-import org.briarproject.bramble.api.plugin.Backoff;
-import org.briarproject.bramble.api.plugin.PluginCallback;
-import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.bramble.api.system.LocationUtils;
-import org.briarproject.bramble.api.system.ResourceProvider;
-import org.briarproject.nullsafety.NotNullByDefault;
-
-import java.io.File;
-import java.util.concurrent.Executor;
-
-import javax.net.SocketFactory;
-
-@NotNullByDefault
-class UnixTorPlugin extends JavaTorPlugin {
-
-	UnixTorPlugin(Executor ioExecutor,
-			Executor wakefulIoExecutor,
-			NetworkManager networkManager,
-			LocationUtils locationUtils,
-			SocketFactory torSocketFactory,
-			Clock clock,
-			ResourceProvider resourceProvider,
-			CircumventionProvider circumventionProvider,
-			BatteryManager batteryManager,
-			Backoff backoff,
-			TorRendezvousCrypto torRendezvousCrypto,
-			PluginCallback callback,
-			String architecture,
-			long maxLatency,
-			int maxIdleTime,
-			File torDirectory,
-			int torSocksPort,
-			int torControlPort) {
-		super(ioExecutor, wakefulIoExecutor, networkManager, locationUtils,
-				torSocketFactory, clock, resourceProvider,
-				circumventionProvider, batteryManager, backoff,
-				torRendezvousCrypto, callback, architecture,
-				maxLatency, maxIdleTime, torDirectory, torSocksPort,
-				torControlPort);
-	}
-
-	@Override
-	protected int getProcessId() {
-		return CLibrary.INSTANCE.getpid();
-	}
-
-	private interface CLibrary extends Library {
-
-		CLibrary INSTANCE = Native.loadLibrary("c", CLibrary.class);
-
-		int getpid();
-	}
-}

bramble-java/src/main/java/org/briarproject/bramble/plugin/tor/UnixTorPluginFactory.java

@@ -3,6 +3,7 @@ package org.briarproject.bramble.plugin.tor;
 import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventExecutor;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.plugin.Backoff;
@@ -13,8 +14,9 @@ import org.briarproject.bramble.api.plugin.TorDirectory;
 import org.briarproject.bramble.api.plugin.TorSocksPort;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
-import org.briarproject.bramble.api.system.ResourceProvider;
 import org.briarproject.bramble.api.system.WakefulIoExecutor;
+import org.briarproject.bramble.plugin.tor.wrapper.TorWrapper;
+import org.briarproject.bramble.plugin.tor.wrapper.UnixTorWrapper;
 import org.briarproject.nullsafety.NotNullByDefault;
 
 import java.io.File;
@@ -34,13 +36,13 @@ public class UnixTorPluginFactory extends TorPluginFactory {
 
 	@Inject
 	UnixTorPluginFactory(@IoExecutor Executor ioExecutor,
+			@EventExecutor Executor eventExecutor,
 			@WakefulIoExecutor Executor wakefulIoExecutor,
 			NetworkManager networkManager,
 			LocationUtils locationUtils,
 			EventBus eventBus,
 			SocketFactory torSocketFactory,
 			BackoffFactory backoffFactory,
-			ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
 			BatteryManager batteryManager,
 			Clock clock,
@@ -48,8 +50,8 @@ public class UnixTorPluginFactory extends TorPluginFactory {
 			@TorDirectory File torDirectory,
 			@TorSocksPort int torSocksPort,
 			@TorControlPort int torControlPort) {
-		super(ioExecutor, wakefulIoExecutor, networkManager, locationUtils,
+		super(ioExecutor, eventExecutor, wakefulIoExecutor, networkManager,
-				eventBus, torSocketFactory, backoffFactory, resourceProvider,
+				locationUtils, eventBus, torSocketFactory, backoffFactory,
 				circumventionProvider, batteryManager, clock, crypto,
 				torDirectory, torSocksPort, torControlPort);
 	}
@@ -62,6 +64,7 @@ public class UnixTorPluginFactory extends TorPluginFactory {
 		if (LOG.isLoggable(INFO)) {
 			LOG.info("System's os.arch is " + arch);
 		}
+		//noinspection IfCanBeSwitch
 		if (arch.equals("amd64")) return "x86_64";
 		else if (arch.equals("aarch64")) return "aarch64";
 		else if (arch.equals("arm")) return "armhf";
@@ -72,11 +75,11 @@ public class UnixTorPluginFactory extends TorPluginFactory {
 	TorPlugin createPluginInstance(Backoff backoff,
 			TorRendezvousCrypto torRendezvousCrypto, PluginCallback callback,
 			String architecture) {
-		return new UnixTorPlugin(ioExecutor, wakefulIoExecutor,
+		TorWrapper tor = new UnixTorWrapper(ioExecutor, eventExecutor,
-				networkManager, locationUtils, torSocketFactory, clock,
+				architecture, torDirectory, torSocksPort, torControlPort);
-				resourceProvider, circumventionProvider, batteryManager,
+		return new TorPlugin(ioExecutor, wakefulIoExecutor, networkManager,
-				backoff, torRendezvousCrypto, callback, architecture,
+				locationUtils, torSocketFactory, circumventionProvider,
-				MAX_LATENCY, MAX_IDLE_TIME, torDirectory, torSocksPort,
+				batteryManager, backoff, torRendezvousCrypto, tor, callback,
-				torControlPort);
+				MAX_LATENCY, MAX_IDLE_TIME, true);
 	}
 }

bramble-java/src/main/java/org/briarproject/bramble/plugin/tor/WindowsTorPluginFactory.java

@@ -3,6 +3,7 @@ package org.briarproject.bramble.plugin.tor;
 import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventExecutor;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.plugin.Backoff;
@@ -13,8 +14,9 @@ import org.briarproject.bramble.api.plugin.TorDirectory;
 import org.briarproject.bramble.api.plugin.TorSocksPort;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
-import org.briarproject.bramble.api.system.ResourceProvider;
 import org.briarproject.bramble.api.system.WakefulIoExecutor;
+import org.briarproject.bramble.plugin.tor.wrapper.TorWrapper;
+import org.briarproject.bramble.plugin.tor.wrapper.WindowsTorWrapper;
 import org.briarproject.nullsafety.NotNullByDefault;
 
 import java.io.File;
@@ -34,13 +36,13 @@ public class WindowsTorPluginFactory extends TorPluginFactory {
 
 	@Inject
 	WindowsTorPluginFactory(@IoExecutor Executor ioExecutor,
+			@EventExecutor Executor eventExecutor,
 			@WakefulIoExecutor Executor wakefulIoExecutor,
 			NetworkManager networkManager,
 			LocationUtils locationUtils,
 			EventBus eventBus,
 			SocketFactory torSocketFactory,
 			BackoffFactory backoffFactory,
-			ResourceProvider resourceProvider,
 			CircumventionProvider circumventionProvider,
 			BatteryManager batteryManager,
 			Clock clock,
@@ -48,8 +50,8 @@ public class WindowsTorPluginFactory extends TorPluginFactory {
 			@TorDirectory File torDirectory,
 			@TorSocksPort int torSocksPort,
 			@TorControlPort int torControlPort) {
-		super(ioExecutor, wakefulIoExecutor, networkManager, locationUtils,
+		super(ioExecutor, eventExecutor, wakefulIoExecutor, networkManager,
-				eventBus, torSocketFactory, backoffFactory, resourceProvider,
+				locationUtils, eventBus, torSocketFactory, backoffFactory,
 				circumventionProvider, batteryManager, clock, crypto,
 				torDirectory, torSocksPort, torControlPort);
 	}
@@ -70,11 +72,11 @@ public class WindowsTorPluginFactory extends TorPluginFactory {
 	TorPlugin createPluginInstance(Backoff backoff,
 			TorRendezvousCrypto torRendezvousCrypto, PluginCallback callback,
 			String architecture) {
-		return new WindowsTorPlugin(ioExecutor, wakefulIoExecutor,
+		TorWrapper tor = new WindowsTorWrapper(ioExecutor, eventExecutor,
-				networkManager, locationUtils, torSocketFactory, clock,
+				architecture, torDirectory, torSocksPort, torControlPort);
-				resourceProvider, circumventionProvider, batteryManager,
+		return new TorPlugin(ioExecutor, wakefulIoExecutor, networkManager,
-				backoff, torRendezvousCrypto, callback, architecture,
+				locationUtils, torSocketFactory, circumventionProvider,
-				MAX_LATENCY, MAX_IDLE_TIME, torDirectory, torSocksPort,
+				batteryManager, backoff, torRendezvousCrypto, tor, callback,
-				torControlPort);
+				MAX_LATENCY, MAX_IDLE_TIME, true);
 	}
 }

bramble-java/src/main/java/org/briarproject/bramble/plugin/tor/wrapper/JavaTorWrapper.java

@@ -0,0 +1,47 @@
+package org.briarproject.bramble.plugin.tor.wrapper;
+
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.io.File;
+import java.io.InputStream;
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.security.CodeSource;
+import java.util.concurrent.Executor;
+
+import static org.briarproject.nullsafety.NullSafety.requireNonNull;
+
+@NotNullByDefault
+abstract class JavaTorWrapper extends AbstractTorWrapper {
+
+	JavaTorWrapper(Executor ioExecutor,
+			Executor eventExecutor,
+			String architecture,
+			File torDirectory,
+			int torSocksPort,
+			int torControlPort) {
+		super(ioExecutor, eventExecutor, architecture, torDirectory,
+				torSocksPort, torControlPort);
+	}
+
+	@Override
+	protected long getLastUpdateTime() {
+		CodeSource codeSource =
+				getClass().getProtectionDomain().getCodeSource();
+		if (codeSource == null) throw new AssertionError("CodeSource null");
+		try {
+			URI path = codeSource.getLocation().toURI();
+			File file = new File(path);
+			return file.lastModified();
+		} catch (URISyntaxException e) {
+			throw new AssertionError(e);
+		}
+	}
+
+	@Override
+	protected InputStream getResourceInputStream(String name,
+			String extension) {
+		ClassLoader cl = getClass().getClassLoader();
+		return requireNonNull(cl.getResourceAsStream(name + extension));
+	}
+}

bramble-java/src/main/java/org/briarproject/bramble/plugin/tor/wrapper/UnixTorWrapper.java

@@ -0,0 +1,35 @@
+package org.briarproject.bramble.plugin.tor.wrapper;
+
+import com.sun.jna.Library;
+import com.sun.jna.Native;
+
+import org.briarproject.nullsafety.NotNullByDefault;
+
+import java.io.File;
+import java.util.concurrent.Executor;
+
+@NotNullByDefault
+public class UnixTorWrapper extends JavaTorWrapper {
+
+	public UnixTorWrapper(Executor ioExecutor,
+			Executor eventExecutor,
+			String architecture,
+			File torDirectory,
+			int torSocksPort,
+			int torControlPort) {
+		super(ioExecutor, eventExecutor, architecture, torDirectory,
+				torSocksPort, torControlPort);
+	}
+
+	@Override
+	protected int getProcessId() {
+		return CLibrary.INSTANCE.getpid();
+	}
+
+	private interface CLibrary extends Library {
+
+		CLibrary INSTANCE = Native.loadLibrary("c", CLibrary.class);
+
+		int getpid();
+	}
+}

bramble-java/src/main/java/org/briarproject/bramble/plugin/tor/wrapper/WindowsTorWrapper.java

@@ -1,54 +1,29 @@
-package org.briarproject.bramble.plugin.tor;
+package org.briarproject.bramble.plugin.tor.wrapper;
 
 import com.sun.jna.platform.win32.Kernel32;
 
-import org.briarproject.bramble.api.battery.BatteryManager;
-import org.briarproject.bramble.api.network.NetworkManager;
-import org.briarproject.bramble.api.plugin.Backoff;
-import org.briarproject.bramble.api.plugin.PluginCallback;
-import org.briarproject.bramble.api.plugin.PluginException;
-import org.briarproject.bramble.api.system.Clock;
-import org.briarproject.bramble.api.system.LocationUtils;
-import org.briarproject.bramble.api.system.ResourceProvider;
 import org.briarproject.nullsafety.NotNullByDefault;
 
 import java.io.File;
+import java.io.IOException;
 import java.util.Scanner;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.Executor;
 
-import javax.net.SocketFactory;
-
 import static java.util.logging.Level.INFO;
 
 @NotNullByDefault
-class WindowsTorPlugin extends JavaTorPlugin {
+public class WindowsTorWrapper extends JavaTorWrapper {
 
-	WindowsTorPlugin(Executor ioExecutor,
+	public WindowsTorWrapper(Executor ioExecutor,
-			Executor wakefulIoExecutor,
+			Executor eventExecutor,
-			NetworkManager networkManager,
-			LocationUtils locationUtils,
-			SocketFactory torSocketFactory,
-			Clock clock,
-			ResourceProvider resourceProvider,
-			CircumventionProvider circumventionProvider,
-			BatteryManager batteryManager,
-			Backoff backoff,
-			TorRendezvousCrypto torRendezvousCrypto,
-			PluginCallback callback,
 			String architecture,
-			long maxLatency,
-			int maxIdleTime,
 			File torDirectory,
 			int torSocksPort,
 			int torControlPort) {
-		super(ioExecutor, wakefulIoExecutor, networkManager, locationUtils,
+		super(ioExecutor, eventExecutor, architecture, torDirectory,
-				torSocketFactory, clock, resourceProvider,
+				torSocksPort, torControlPort);
-				circumventionProvider, batteryManager, backoff,
-				torRendezvousCrypto, callback, architecture,
-				maxLatency, maxIdleTime, torDirectory, torSocksPort,
-				torControlPort);
 	}
 
 	@Override
@@ -58,7 +33,7 @@ class WindowsTorPlugin extends JavaTorPlugin {
 
 	@Override
 	protected void waitForTorToStart(Process torProcess)
-			throws InterruptedException, PluginException {
+			throws InterruptedException, IOException {
 		// On Windows the RunAsDaemon option has no effect, so Tor won't detach.
 		// Wait for the control port to be opened, then continue to read its
 		// stdout and stderr in a background thread until it exits.
@@ -91,7 +66,7 @@ class WindowsTorPlugin extends JavaTorPlugin {
 			}
 		});
 		// Wait for the startup result
-		if (!success.take()) throw new PluginException();
+		if (!success.take()) throw new IOException();
 	}
 
 	@Override

bramble-java/src/test/java/org/briarproject/bramble/plugin/tor/BridgeTest.java

@@ -5,6 +5,7 @@ import org.briarproject.bramble.api.Multiset;
 import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventExecutor;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.plugin.BackoffFactory;
@@ -113,6 +114,9 @@ public class BridgeTest extends BrambleTestCase {
 	@IoExecutor
 	Executor ioExecutor;
 	@Inject
+	@EventExecutor
+	Executor eventExecutor;
+	@Inject
 	@WakefulIoExecutor
 	Executor wakefulIoExecutor;
 	@Inject
@@ -185,9 +189,9 @@ public class BridgeTest extends BrambleTestCase {
 				return singletonList(params.bridge);
 			}
 		};
-		factory = new UnixTorPluginFactory(ioExecutor, wakefulIoExecutor,
+		factory = new UnixTorPluginFactory(ioExecutor, eventExecutor,
-				networkManager, locationUtils, eventBus, torSocketFactory,
+				wakefulIoExecutor, networkManager, locationUtils, eventBus,
-				backoffFactory, resourceProvider, bridgeProvider,
+				torSocketFactory, backoffFactory, bridgeProvider,
 				batteryManager, clock, crypto, torDir, torSocksPort,
 				torControlPort);
 	}
@@ -207,7 +211,7 @@ public class BridgeTest extends BrambleTestCase {
 		DuplexPlugin duplexPlugin =
 				factory.createPlugin(new TestPluginCallback());
 		assertNotNull(duplexPlugin);
-		UnixTorPlugin plugin = (UnixTorPlugin) duplexPlugin;
+		TorPlugin plugin = (TorPlugin) duplexPlugin;
 
 		LOG.warning("Testing " + params.bridge);
 		try {